Polysilanes and process for preparation of same

ABSTRACT

The invention is directed to a polysilane represented by the formula (1)                    
     wherein R is hydrogen atom, alkyl group, aryl group, alkoxy group, amino group or silyl group, R&#39;s may be the same or at least two of them may be different from each other; each hydroxyl group is in the p-position or m-position; and n is 2 to 10,000, preferably 13 to 8,500. The polysilane of the invention is important as materials for modified polycarbonates or like engineering plastics, resists or electrophotographic photoreceptors.

TECHNICAL FIELD

The present invention relates to novel polysilanes regarded important asstarting materials for engineering plastics such as modifiedpolycarbonates, as materials for resists or as materials forelectrophotographic photoreceptors, and to a process for preparing thesame.

BACKGROUND ART

Investigations have been made on the use of engineering plastics, e.g.polycarbonate, as a material for hard coat. In fact, some of suchplastics have been in actual use. However, bisphenol A polycarbonate isnot satisfactory in hardness and has been modified to increase thehardness.

The polysilanes having phenol groups at both ends according to thepresent invention can be used as a starting material for producing apolycarbonate or polyester having a polysilane skeleton in the mainchain. Thus, when the polysilane of the invention is used, apolycarbonate or the like with improved hardness can be prepared and amore useful material for hard coat can be provided. Further the obtainedpolycarbonate or the like with a polysilane skeleton has aphotosensitive property and a charge-transporting property derived fromthe polysilane and is usable as a new type of hard coat material showingan optoelectronic function.

However, no research has been conducted on such polysilanes with phenolgroups at both ends which are useful in producing a modifiedpolycarbonate or the like. No process for preparing the polysilanes isknown.

Further it is needless to say that a process was unknown for preparingsuch polysilanes having phenol groups at both ends wherein the degree ofpolymerization of polysilane is controlled and phenol groups areintroduced at both ends in order to produce a modified polycarbonate orthe like having properties optimal for various applications as a hardcoat material.

DISCLOSURE OF THE INVENTION

An object of the present invention is to provide a novel polysilanewhich is important as a starting material for engineering plastics suchas modified polycarbonates, as a material for resists or as a materialfor electrophotographic photoreceptors.

Another object of the invention is to provide a process for preparingsuch novel polysilane.

In view of the foregoing situation of the prior art, the inventors ofthis invention conducted extensive research and found out a process forpreparing the desired polysilane by reacting a polysilane having halogenatoms at both ends with a Grignard reagent prepared by reactingmagnesium with a hydroxyl-protected halogenated phenol or ahydroxyl-protected halogenated phenol derivative, followed bydeprotection.

The inventors also discovered a process for preparing a polysilanehaving phenol groups at both ends in a manner to control the degree ofpolymerization in the polysilane moiety, the polysilane being useful inproducing a modified polycarbonate having properties optimal for variousapplications as a hard coat material, the process comprising conductingan electrode reaction using a specific metal as the anode or a reductionreaction using a specific metal in the presence of a specific lithiumsalt and a specific halogenated metal to give a polysilane havinghalogen atoms at both ends.

According to the present invention, there are provided the followingpolysilanes having phenol groups at both ends and processes forpreparing the same.

1. A polysilane represented by the formula (1)

wherein R is hydrogen atom, alkyl group, aryl group, alkoxy group, aminogroup or silyl group; R's may be the same or at least two of them may bedifferent from each other; each hydroxyl group is in the p-position orm-position; and n is 2 to 10,000.

2. The polysilane as defined in item 1, wherein n is 5 to 8,500.

3. The polysilane as defined in item 1, wherein n is 13 to 8,500.

4. A process for preparing a polysilane having phenol groups at bothends which is represented by the formula (1)

wherein R is hydrogen atom, alkyl group, aryl group, alkoxy group, aminogroup or silyl group; R's may be the same or at least two of them may bedifferent from each other; each hydroxyl group is in the p-position orm-position; and n is 2 to 10,000, the process comprising the steps of(a) conducting the Grignard reaction between (i) a polysilane havinghalogen atoms at both ends which is represented by the formula (2)

wherein R and n are as defined above; and X is halogen atom, and (ii) aGrignard reagent prepared by reacting magnesium with ahydroxyl-protected halogenated phenol represented by the formula (3)

wherein R₁ is hydroxyl-protecting group, and represents alkyl group,alkoxyalkyl group, silyl group, acyl group, alkylthioalkyl group oralkylsulfoxy group; protected hydroxyl group is in the p-position orm-position; and X₁ is halogen atom, thereby producing a polysilanerepresented by the formula (4)

wherein R, R₁, the position of protected hydroxyl group and n are asdefined above although variant depending on the starting materials; and(b) reacting the polysilane of the formula (4) with an acid.

5. The process for preparing a polysilane having phenol groups at bothends as defined in item 4, the process being characterized in that thepolysilane having halogen atoms at both ends which is represented by theformula (2)

wherein R is hydrogen atom, alkyl group, aryl group, alkoxy group, aminogroup or silyl group; R's may be the same or at least two of them may bedifferent from each other; n is 2 to 10,000; and X is halogen atom, isproduced by subjecting to an electrode reaction a dihalosilanerepresented by the formula (5)

wherein m is 1 to 3; R is hydrogen atom, alkyl group, aryl group, alkoxygroup, amino group or silyl group; 2 R's in the case of m=1, 4 R's inthe case of m=2, or 6 R's in the case of m=3 may be the same or at leasttwo of them may be different from each other; and X is halogen atom,using Mg or a Mg-based alloy as the anode, a lithium salt as asupporting electrolyte and an aprotic solvent as a solvent with orwithout use of a halogenated metal as a current carrying aid.

6. The process for preparing a polysilane having phenol groups at bothends as defined in item 4, the process being characterized in that thepolysilane having halogen atoms at both ends which is represented by theformula (2)

wherein R is hydrogen atom, alkyl group, aryl group, alkoxy group, aminogroup or silyl group; R's may be the same or at least two of them may bedifferent from each other; n is 2 to 10,000; and X is halogen atom, isproduced by reducing a dihalosilane represented by the formula (5)

wherein m is 1 to 3; R is hydrogen atom, alkyl group, aryl group, alkoxygroup, amino group or silyl group; 2 R's in the case of m=1, 4 R's inthe case of m=2, or 6 R's in the case of m=3 may be the same or at leasttwo of them may be different from each other; and X is halogen atom,using Mg or Mg-based alloy in an aprotic solvent in the presence of alithium salt and a halogenated metal.

7. A polysilane represented by the formula (6)

wherein R is hydrogen atom, alkyl group, aryl group, alkoxy group, aminogroup or silyl group; R's may be the same or at least two of them may bedifferent from each other; Y is CH₂, C₂H₄, C₃H₆, C₄H₈, O or S; eachhydroxyl group is in the p-position or m-position; and n is 2 to 10,000.

8. The polysilane as defined in item 7, wherein n is 5 to 8,500.

9. The polysilane as defined in item 7, wherein n is 13 to 8,500.

10. A process for preparing a polysilane having phenol groups at bothends which is represented by the formula (6)

wherein R is hydrogen atom, alkyl group, aryl group, alkoxy group, aminogroup or silyl group; R's may be the same or at least two of them may bedifferent from each other; Y is CH₂, C₂H₄, C₃H₆, C₄H₈, O or S; eachhydroxyl group is in the p-position or m-position; and n is 2 to 10,000,the process comprising the steps of (a) conducting the Grignard reactionbetween (i) a polysilane having halogen atoms at both ends which isrepresented by the formula (2)

wherein R and n are as defined above; and X is halogen atom, and (ii) aGrignard reagent prepared by reacting magnesium with ahydroxyl-protected halogenated phenol derivative represented by theformula (7)

wherein R₁ is hydroxyl-protecting group, and represents alkyl group,alkoxyalkyl group, silyl group, acyl group, alkylthioalkyl group oralkylsulfoxy group; Y is CH₂, C₂H₄, C₃H₆, C₄H₈, O or S; protectedhydroxyl group is in the p-position or m-position; and X₁ is halogenatom, thereby producing a polysilane represented by the formula (8)

wherein R, R₁, Y, the position of protected hydroxyl group and n are asdefined above although variant depending on the starting materials; and(b) reacting the obtained polysilane with an acid.

11. The process for preparing a polysilane having phenol groups at bothends as defined in item 10, the process being characterized in that thepolysilane having halogen atoms at both ends which is represented by theformula (2)

wherein R is hydrogen atom, alkyl group, aryl group, alkoxy group, aminogroup or silyl group; R's may be the same or at least two of them may bedifferent from each other; n is 2 to 10,000; and X is halogen atom, isproduced by subjecting to an electrode reaction a dihalosilanerepresented by the formula (5)

wherein m is 1 to 3; R is hydrogen atom, alkyl group, aryl group, alkoxygroup, amino group or silyl group; 2 R's in the case of m=1, 4 R's inthe case of m=2, or 6 R's in the case of m=3 may be the same or at leasttwo of them may be different from each other; and X is halogen atom,using Mg or a Mg-based alloy as the anode, a lithium salt as asupporting electrolyte and an aprotic solvent as a solvent with orwithout use of a halogenated metal as a current carrying aid.

12. The process for preparing a polysilane having phenol groups at bothends as defined in item 10, the process being characterized in that thepolysilane having halogen atoms at both ends which is represented by theformula (2)

wherein R is hydrogen atom, alkyl group, aryl group, alkoxy group, aminogroup or silyl group; R's may be the same or at least two of them may bedifferent from each other; n is 2 to 10,000; and X is halogen atom, isproduced by reducing a dihalosilane represented by the formula (5)

wherein m is 1 to 3; R is hydrogen atom, alkyl group, aryl group, alkoxygroup, amino group or silyl group; 2 R's in the case of m=1, 4 R's inthe case of m=2, or 6 R's in the case of m=3 may be the same or at leasttwo of them may be different from each other; and X is halogen atom,using Mg or Mg-based alloy in an aprotic solvent in the presence of alithium salt and a halogenated metal.

Hereinafter “the invention recited in claim 1 of independent form andthe inventions recited in claims dependent thereon” are called “firstinvention in the present application”, and all the inventions arecollectively called merely “the present invention”.

1. First Invention in the Present Application

The polysilane of the first invention in the present application is anovel compound represented by the formula (1)

wherein R is hydrogen atom, alkyl group, aryl group, alkoxy group, aminogroup or silyl group, R's may be the same or at least two of them may bedifferent from each other; each hydroxyl group is in the p-position orm-position; and n is 2 to 10,000.

In the polysilane represented by the formula (1), R represents hydrogenatom, alkyl group, aryl group, alkoxy group, amino group or silyl group.The alkyl groups in the formula (1) include those having 1 to 10 carbonatoms among which those having 1 to 6 carbon atoms are more preferred.The aryl groups in the formula (1) include phenyl group, anisyl group,phenyl group having at least one of alkyl groups of 1 to 10 carbon atomsas a substituent, p-alkoxyphenyl group, and naphthyl group. The alkoxygroups in the formula (1) include those having 1 to 10 carbon atomsamong which those having 1 to 6 carbon atoms are more preferred. Thesilyl groups in the formula (1) include those having 1 to 10 siliconatoms among which those having 1 to 6 silicon atoms are more preferred.When R is amino group, organic substituent or silyl group, at least oneof hydrogen atoms may be substituted with other groups such as alkyl,aryl or alkoxy group. Such functional groups include those describedabove. R's may be the same or at least two of them may be different fromeach other. The hydroxyl group is in the p-position or m-position on thebenzene ring of phenol groups at both ends. The hydroxyl groups at twoends may be both in the p-position or both in the m-position, or one ofthem may be in the p-position and the other in the m-position.Optionally at least one of hydrogen atoms on the benzene ring may besubstituted with other groups such as alkyl or aryl group. The alkyl andaryl groups for this purpose include those described above. The symbol nmeans 2 to 10,000, preferably 5 to 8,500, more preferably 13 to 8,500.

2. Second Invention in the Present Application

The second invention is directed to a process for preparing thepolysilane of the first invention in the present application. In thesecond invention, the Grignard reaction is carried out using, as thestarting materials, (i) a polysilane having halogen atoms at both endswhich is represented by the formula (2)

wherein R is hydrogen atom, alkyl group, aryl group, alkoxy group, aminogroup or silyl group; R's may be the same or at least two of them may bedifferent from each other; n is 2 to 10,000; and X is halogen atom, and(ii) a Grignard reagent prepared by reacting magnesium with ahydroxyl-protected halogenated phenol represented by the formula (3)

wherein R₁ is hydroxyl-protecting group, and represents alkyl group,alkoxyalkyl group, silyl group, acyl group, alkylthioalkyl group oralkylsulfoxy group; protected hydroxyl group is in the p-position orm-position; and X₁ is halogen atom.

In the formula (2), R and n are the same in detail as in the firstinvention, X is halogen atom (Cl, F, Br or I) and Cl is preferred.

In the formula (3), X₁ is halogen atom (Cl, F, Br or I) and Br or I ispreferred.

The polysilane having halogen atoms at both ends which is represented bythe formula (2) can be prepared by (i) an electrode reaction using aspecific metal as the anode (electrode reduction synthesis method:Japanese Unexamined Patent Publication No.309953/1995), (ii) a synthesismethod wherein polymerization is conducted by reduction using a specificmetal in the presence of a specific lithium salt and a halogenated metal(chemical polymerization method), or (iii) a dechlorinating condensationpolymerization by reduction in toluene or like solvent using an alkalimetal such as sodium metal at a high temperature at which the solvent isrefluxed (Kipping method: J. Am. Chem. Soc., 103 (1981) 7352).

The electrode reduction synthesis method (i) and Kipping method (iii)are known and the chemical polymerization method (ii) is novel.

The degree of polymerization of a polysilane with halogen atoms at bothends significantly affects the properties of a modified polycarbonatehaving a polysilane skeleton in the main chain. In other words, theelectrode reduction synthesis method and chemical polymerization methodare preferred because the methods can easily control the degree ofpolymerization in producing a polysilane with halogen atoms at both endsand can produce a polysilane with a low degree of polymerization.

When a polysilane having halogen atoms at both ends is prepared by theelectrode reduction synthesis method, at least one of dihalosilanesrepresented by the following formula (5)

wherein m is 1 to 3; R is hydrogen atom, alkyl group, aryl group, alkoxygroup, amino group or silyl group; 2 R's in the case of m=1, 4 R's inthe case of m=2, or 6 R's in the case of m=3 may be the same or at leasttwo of them may be different from each other; and X is halogen atom, issubjected to an electrode reaction using Mg or a Mg-based alloy as theanode, a lithium salt as a supporting electrolyte and an aprotic solventas a solvent with or without use of a halogenated metal as a currentcarrying aid.

In the formula (5), R and X are the same in detail as above.

In the reaction, the dihalosilane is used as dissolved in a solvent.Aprotic solvents useful as the solvent include those widely used.Specific examples are ether solvents such as tetrahydrofuran,1,2-dimethoxyethane, bis(2-methoxyethyl)ether and 1,4-dioxane, propylenecarbonate, acetonitrile, dimethylformamide, dimethyl sulfoxide andmethylene chloride. These solvents are usable either alone or incombination. More preferred solvents are tetrahydrofuran and1,2-dimethoxyethane. Too low a concentration of the dihalosilane in thesolvent lowers the current efficiency, whereas too high a concentrationthereof may result in failure to dissolve the supporting electrolyte.Consequently the concentration of the dihalosilane in the solvent is inthe range of about 0.05 to about 20 mol/l, preferably about 0.2 to about15 mol/l, more preferably about 0.3 to about 13 mol/l.

Supporting electrolytes to be used are, for example, lithium salts suchas LiCl, LiNO₃, Li₂CO₃ and LiClO₄. These supporting electrolytes areusable either alone or in combination. Of these supporting electrolytes,LiCl is the most preferred.

The concentration of the supporting electrolyte in the solvent is about0.05 to about 5 mol/l, preferably about 0.1 to 3 mol/l, more preferablyabout 0.15 to about 2 mol/l.

To improve current conductivity, a current carrying aid may be used.Favorable current carrying aids include Al salts such as AlCl₃; Fe saltssuch as FeCl₂ and FeCl₃; Mg salts such as MgCl₂; Zn salts such as ZnCl₂;Sn salts such as SnCl₂; Co salts such as CoCl₂; Pd salts such as PdCl₂;V salts such as VCl₃; Cu salts such as CuCl₂; and Ca salts such asCaCl₂. These current carrying aids are usable either alone or incombination. Of these current carrying aids, more preferred are AlCl₃,FeCl₂, FeCl₃, CoCl₂ and CuCl₂. The concentration of the current carryingaid in the solvent is in the range of about 0.01 to about 6 mol/l,preferably about 0.03 to about 4 mol/l, more preferably about 0.05 toabout 3 mol/l.

The anodes to be used herein are made of Mg or an alloy predominantlycontaining Mg. Examples of the alloy predominantly containing Mg arealloys containing about 3 to about 10% of Al. The cathodes to be usedherein are unlimited insofar as they are substances through which acurrent can flow. Examples include stainless steel such as SUS 304 andSUS 316; metals such as Mg, Cu, Zn, Sn, Al, Ni and Co; and carbonmaterials.

The amount of electricity applied is at least about 1 F/mol based on thehalogen in the dihalosilane. The molecular weight of the reactionproduct can be controlled by adjusting the amount of electricityapplied.

On the other hand, the chemical polymerization method is conducted asfollows. Mg or Mg-based alloy is acted on at least one of dihalosilanesrepresented by the formula (5) in an aprotic solvent in the presence ofa specific lithium salt and a halogenated metal, giving a polysilane.The dihalosilane is reduced with Mg or Mg-based alloy to polymerize,forming a polysilane. The Mg or Mg-based alloy is consumed to become ahalogenated Mg.

Examples of useful aprotic solvents are polar solvents such astetrahydrofuran, 1,2-dimethoxyethane, propylene carbonate, acetonitrile,dimethylformamide, dimethyl sulfoxide, bis(2-methoxyethyl)ether,1,4-dioxane and methylene chloride; and non-polar solvents such astoluene, xylene, benzene, n-pentane, n-hexane, n-octane, n-decane andcyclohexane. These solvents can be used either alone or in combination.Preferable to use are polar solvents used alone, a mixture of at least 2species of polar solvents, and a mixture of polar and non-polarsolvents. When the mixture of polar and non-polar solvents is used, itis preferred to mix them at a former:latter ratio of approximately1:0.01-20. Tetrahydrofuran and 1,2-dimethoxyethane are more preferred asa polar solvent to be used alone or in combination with other solvents.The concentration of the dihalosilane in the solvent is in the range ofabout 0.05 to about 20 mol/l, preferably about 0.2 to about 15 mol/l,more preferably about 0.3 to about 13 mol/l.

Examples of the specific lithium salt are LiCl, LiNO₃, Li₂CO₃ andLiClO₄. These lithium salts can be used either alone or in combination.Among them, LiCl is the most preferred.

The concentration of the lithium salt in the solvent is in the range ofabout 0.05 to about 5 mol/l, preferably about 0.1 to about 3 mol/l, morepreferably about 0.15 to about 2 mol/l.

Examples of the specific halogenated metal are FeCl₂, FeCl₃, FeBr₂,FeBr₃, AlCl₃, AlBr₃, ZnCl₂, SnCl₂, SnCl₄, CuCl₂, CoCl₂, VCl₃, TiCl₄,PdCl₂, SmCl₂ and SmI₂. Of these halogenated metals, more preferable touse are FeCl₂, ZnCl₂ and CuCl₂. The concentration of the halogenatedmetal in the solvent is in the range of about 0.01 to about 6 mol/l,preferably about 0.02 to about 4 mol/l, more preferably about 0.03 toabout 3 mol/l.

The shape of Mg or Mg-based alloy is not limited insofar as the reactionis feasible. Examples are powders, granules, ribbons, flakes (producedby cutting), masses, rods and plates. Among them, preferred are powders,granules, ribbons and flakes which have a large specific surface area.As to the amount of Mg or Mg-based alloy to be used, the amount of Mg isan at least equimolar amount relative to the dihalosilane used and theamount of Mg-based alloy is such that the Mg content in the Mg-basedalloy is an at least equimolar amount relative to the dihalosilane used.When the amount of Mg or Mg content in a Mg-based alloy to be used ismore than an equimolar amount relative to the dihalosilane used, thereaction time is shortened. Thus the amount thereof is preferably atleast 1.5 mols, more preferably at least 2 mols, per mole of thedihalosilane used.

The chemical polymerization method can be carried out, for example, asfollows. The dihalosilane of the formula (5) is placed into a sealablecontainer, along with a lithium salt, a halogenated metal, Mg orMg-based alloy and a solvent, preferably followed by mechanical ormagnetic agitation to cause a reaction. The shape of the reactor is notlimited insofar as it is hermetically closable.

The reaction time is variable depending on the amounts of a dihalosilaneas the raw material, Mg or Mg-based alloy, a lithium salt and ahalogenated metal all used together and depending on the stirring speed.Usually it is about 30 minutes or more. The molecular weight of thereaction product can be controlled by adjusting the reaction time. Whenthe chemical polymerization method is conducted, a more preferred degreeof polymerization is 5 to 1,000.

The reaction temperature is in the range of from −20° C. to a boilingpoint of the solvent used, preferably about −10 to about 50° C., morepreferably about −5 to about 30° C.

The Grignard reagent is prepared by reacting Mg with thehydroxyl-protected halogenated phenol of the formula (3). Halogenatedphenols to be used are known and include those commercially availablesuch as p-bromophenol, m-bromophenol or p-chlorophenol. The hydroxylgroup can be protected by conventional methods, for example, a methodusing, as R₁, alkyl groups such as methyl or ethyl (Org. Synth., Coll.Vol.4, 836 (1963)); a method using, as R₁, alkoxyalkyl groups such asmethoxymethyl, butoxymethyl, tetrahydropyranyl or tetrahydrofuranyl(Tetrahedron Lett., 661 (1978)); a method using, as R₁, silyl groupssuch as trimethylsilyl or t-butyldimethylsilyl (Tetrahedron Lett., 3527(1970)); a method using, as R₁, acyl groups such as acetyl (TetrahedronLett., 2431 (1979)); a method using, as R₁, alkylthioalkyl groups suchas methylthiomethyl (Tetrahedron Lett., 533 (1977)); and a method using,as R₁, alklylsulfoxy groups such as methanesulfoxy or p-toluenesulfoxy(J. Org., Chem., 32,1058 (1967)).

The Grignard reagent can be prepared by conventional methods. Therequired amount of Mg is 1 mol or more per mol of the hydroxyl-protectedhalogenated phenol, usually in the range of 1 to 2 mols.

Useful solvents include those conventionally used in the Grignardreaction such as diethyl ether or tetrahydrofuran. The concentration ofthe hydroxyl-protected halogenated phenol in the solvent is in the rangeof about 0.1 to about 20 mol/l, preferably about 0.2 to about 8 mol/l,more preferably about 0.3 to about 5 mol/l.

In conducting the Grignard reaction, the polysilane having halogen atomsin both ends which is represented by the formula (2) is concentrated bydistilling off the solvent and is added to the Grignard reagentsolution.

The Grignard reaction is usually carried out by stirring at roomtemperature, or by heating or cooling at a temperature at which thereaction proceeds. The stirring time is usually about 0.1 to about 36hours.

If a solvent useful in the Grignard reaction such as tetrahydrofuran isused in preparing the polysilane halogenated at both ends,advantageously the reaction mixture can be added to the Grignard reagentsolution without distilling off the solvent.

After completion of the reaction, water is added to inactivate theexcess Grignard reagent. Then, the mixture is extracted to give apolysilane having phenol groups at both ends, the phenol groupscontaining hydroxyl groups protected, the polysilane being representedby the formula (4)

wherein R, R₁, the position of protected hydroxyl group and n are asdefined above although variant depending on the starting materials.

The hydroxyl groups in the obtained polysilane are deprotected, therebyproducing a polysilane having phenol groups at both ends which isrepresented by the formula (1). The hydroxyl groups are deprotected bymethods selected according to the type of protecting group. Thedeprotection may be effected by treating the protected hydroxyl groupwith hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid,perchloric acid, or organic acids such as p-toluenesulfonic acid,trichloroacetic acid, trifluoroacetic acid or nitrophenol, followed bystirring for about 0.1 to about 48 hours.

The above-obtained polysilane having phenol groups at both ends which isrepresented by the formula (1) may contain impurities such as phenolsevolved due to the excess Grignard reagent. The impurities, however, canbe easily removed by washing the polysilane with methanol, ethanol,water or a mixture thereof.

3. Third Invention in the Present Application

The polysilane of the third invention in the present application is anovel polysilane represented by the formula (6)

wherein R is hydrogen atom, alkyl group, aryl group, alkoxy group, aminogroup or silyl group; R's may be the same or at least two of them may bedifferent from each other; Y is CH₂, C₂H₄, C₃H₆, C₄H₈, O or S; eachhydroxyl group is in the p-position or m-position; and n is 2 to 10,000.

In the polysilane of the formula (6), R represents hydrogen atom, alkylgroup, aryl group, alkoxy group, amino group or silyl group. Usefulalkyl groups include those having 1 to 10 carbon atoms. Among them,those having 1 to 6 carbon atoms are more preferred. The aryl groups inthe formula (6) include phenyl group, anisyl group, phenyl group havingat least one of alkyl groups of 1 to 10 carbon atoms as a substituent,p-alkoxyphenyl group and naphthyl group. The alkoxy groups in theformula (6) include those having 1 to 10 carbon atoms. Of these groups,those having 1 to 6 carbon atoms are more preferred. The silyl groups inthe formula (6) include those having 1 to 10 silicon atoms among whichthose having 1 to 6 silicon atoms are more preferred. When R is aminogroup, organic substituent or silyl group, at least one of hydrogenatoms may be substituted with other groups such as alkyl, aryl or alkoxygroup. Such functional groups include those described above. R's may bethe same or at least two of them may be different from each other. Y isCH₂, C₂H₄, C₃H₆, C₄H₈, O or S. Each hydroxyl group is in the p-positionor m-position on the benzene ring of phenol groups at both ends. Thehydroxyl groups at two ends may be both in the p-position or both in them-position, or one of them may be in the p-position and the other in them-position. Optionally at least one of hydrogen atoms on the benzenering may be substituted with other groups such as alkyl or aryl group.The alkyl and aryl groups for this purpose include those describedabove. The symbol n means 2 to 10,000, preferably 5 to 8,500, morepreferably 13 to 8,500.

4. Fourth Invention in the Present Application

The fourth invention in the present application is essentially the sameas the second invention except that a hydroxyl-protected halogenatedphenol derivative represented by the following formula (7) is used inlieu of the hydroxyl-protected halogenated phenol

wherein R₁ is hydroxyl-protecting group, and represents alkyl group,alkoxyalkyl group, silyl group, acyl group, alkylthioalkyl group oralkylsulfoxy group; Y is CH₂, C₂H₄, C₃H₆, C₄H₈, O or S; protectedhydroxyl group is in the p-position or m-position; and X₁ is halogenatom.

In the hydroxyl-protected halogenated phenol derivative represented bythe formula (7), Y is CH₂, C₂H₄, C₃H₆, C₄H₈, O or S.

The halogenated phenol derivatives to be used are known. For example,p-(β-bromoethyl)phenol can be easily produced by reacting hydrobromicacid with p-(β-hydroxyethyl)phenol commercially available. Otherhalogenated phenol derivatives include, for example,m-(β-bromoethyl)phenol and p-(γ-bromopropyl)phenol.

The hydroxyl group can be deprotected by conventional methods, e.g. inthe same manner as described in the second invention.

Also in the fourth invention, the degree of polymerization of thepolysilane halogenated at both ends which is represented by the formula(2) greatly affects the properties of modified polycarbonates having apolysilane skeleton in the main chain. For this reason, the electrodereduction synthesis method and chemical polymerization method arepreferably utilizable in producing a polysilane with halogen atoms atboth ends because the methods easily control the degree ofpolymerization and can produce a polysilane with a low degree ofpolymerization.

In the same manner as in the second invention, the hydroxyl groups canbe deprotected in the polysilane of the following formula (8) preparedby the Grignard reaction

wherein R, R₁, Y, the position of protected hydroxyl group and n are asdefined above although variant with the starting materials, giving apolysilane of the formula (6).

According to the present invention, the following remarkable results areachieved.

(a) When using a polysilane having phenol groups at both ends accordingto the present invention, a polycarbonate or polyester having apolysilane skeleton in the main chain can be produced with improvedhardness, and a more useful hard coat material can be provided.

(b) The polycarbonate or the like with a polysilane skeleton preparedfrom the polysilane having phenol groups at both ends according to thepresent invention has a photosensitive property and acharge-transporting property derived from the polysilane, and can beused to provide a new type of hard coat material having anoptoelectronic function.

(c) When the electrode reduction synthesis method or chemicalpolymerization method is conducted, the degree of polymerization of apolysilane with phenol groups at both ends can be controlled, making itpossible to give a modified polycarbonate or the like having propertiesoptimal for various applications as a hard coat material.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a ¹H-NMR chart of the polysilane prepared in Example 27.

FIG. 2 is an IR chart of the polysilane prepared in Example 27.

FIG. 3 is a UV chart of the polysilane prepared in Example 27.

FIG. 4 is a ¹H-NMR chart of the polysilane prepared in Example 28.

FIG. 5 is an IR chart of the polysilane prepared in Example 28.

FIG. 6 is a UV chart of the polysilane prepared in Example 28.

FIG. 7 is a ¹H-NMR chart of the polysilane prepared in Example 36.

FIG. 8 is an IR chart of the polysilane prepared in Example 36.

FIG. 9 is a UV chart of the polysilane prepared in Example 36.

FIG. 10 is a ¹H-NMR chart of the polysilane prepared in Example 40.

FIG. 11 is a UV chart of the polysilane prepared in Example 40.

FIG. 12 is a ¹H-NMR chart of the polysilane prepared in Example 42.

FIG. 13 is a UV chart of the polysilane prepared in Example 42.

FIG. 14 is a ¹H-NMR chart of the polysilane prepared in Example 44.

FIG. 15 is a UV chart of the polysilane prepared in Example 44.

BEST MODE OF CARRYING OUT THE INVENTION

The following examples are given to clarify the features of the presentinvention.

Examples 1-9 given below are illustrative of the synthesis ofpolysilanes with halogen atoms at both ends by the electrode reductionsynthesis method.

EXAMPLE 1

Seventeen grams of anhydrous lithium chloride (LiCl) and 10 g ofanhydrous ferrous chloride (FeCl₂) were placed into a 800 ml-vol.electrolysis vessel equipped with an anode made of Mg (electrode area 63cm²) and a cathode made of stainless steel (SUS 304) (electrode area 63cm²). The air in the electrolysis vessel was replaced by deoxidized dryargon. Added were 650 ml of tetrahydrofuran (THF) predried oversodium-benzophenone ketyl and 64 g (0.33 mol) ofmethylphenyldichlorosilane purified by distillation. While the reactionsolution was stirred and maintained at 20° C., an electric current wasapplied from a constant current power source. The current was applied topass 3.5 F/mol of electricity based on methylphenyldichlorosilane.

After completion of current application, the molecular weight of thereaction product was measured. The product was found to have a weightaverage molecular weight of 19,000 (average degree of polymerizationabout 158). A mass spectrometric analysis confirmed that the reactionproduct was chlorinated at both ends.

EXAMPLE 2

The procedure of Example 1 was repeated except that the passedelectricity was 2.5 F/mol. The reaction product was found to have aweight average molecular weight of 10,800 (average degree ofpolymerization about 90).

EXAMPLE 3

The procedure of Example 1 was repeated except that the passedelectricity was 2.0 F/mol. The reaction product was found to have aweight average molecular weight of 5,800 (average degree ofpolymerization about 48).

EXAMPLE 4

The procedure of Example 1 was repeated except that the passedelectricity was 1.5 F/mol. The reaction product was found to have aweight average molecular weight of 1,100 (average degree ofpolymerization about 9).

EXAMPLE 5

The procedure of Example 1 was repeated except that 73 g (0.33 mol) ofp-ethylphenylmethyldichlorosilane was used as the raw material. Thereaction product was found to have a weight average molecular weight of23,000 (average degree of polymerization about 155).

EXAMPLE 6

The procedure of Example 1 was repeated except that 82 g (0.33 mol) ofp-butylphenylmethyldichlorosilane was used as the raw material. Thereaction product was found to have a weight average molecular weight of21,500 (average degree of polymerization about 122).

EXAMPLE 7

The procedure of Example 1 was repeated except that 65 g (0.33 mol) ofcyclohexylmethyldichlorosilane was used as the raw material. Thereaction product was found to have a weight average molecular weight of13,300 (average degree of polymerization about 106).

EXAMPLE 8

The procedure of Example 1 was repeated except that 32 g (0.16 mol) ofmethylphenyldichlorosilane and 21 g (0.16 mol) of dimethyldichlorosilanewere used as the raw materials. The reaction product had a weightaverage molecular weight of 16,100.

EXAMPLE 9

The procedure of Example 1 was repeated except that 57 g (0.30 mol) ofmethylphenyldichlorosilane and 4 g (0.03 mol) of dimethyldichlorosilanewere used as the raw materials. The reaction product had a weightaverage molecular weight of 14,700.

Examples 10 to 26 described below illustrate the synthesis ofpolysilanes halogenated at both ends by the chemical polymerizationmethod.

EXAMPLE 10

Into a 1-liter vol. eggplant type flask equipped with a three waystop-cock were placed 60 g of granular magnesium (about 1 mm in particlesize), 16 g of anhydrous lithium chloride (LiCl) and 9.6 g of anhydrousferrous chloride (FeCl₂). The mixture was dried with heating to 50° C.under a reduced pressure of 1 mmHg. Dry argon gas was introduced intothe reactor. Added were 600 ml of tetrahydrofuran (THF) predried oversodium-benzophenone ketyl, followed by 30 minutes of stirring at roomtemperature. Sixty-four grams (0.33 mol) of methylphenyldichlorosilanepurified by distillation was added with a syringe. The mixture wasstirred at room temperature for about 12 hours.

After completion of the reaction, the molecular weight of the reactionproduct was measured. It was found that the reaction product had aweight average molecular weight of 18,300 (average degree ofpolymerization about 153). A mass spectrometric analysis confirmed thatthe reaction product was chlorinated at both ends.

EXAMPLE 11

The procedure of Example 10 was repeated except that the mixture wasstirred for 10 hours after addition of methylphenyldichlorosilane. Thereaction product had a weight average molecular weight of 11,900(average degree of polymerization about 99).

EXAMPLE 12

The procedure of Example 10 was conducted except that the mixture wasstirred for 7 hours after addition of methylphenyldichlorosilane. Thereaction product had a weight average molecular weight of 5,500 (averagedegree of polymerization about 46).

EXAMPLE 13

The procedure of Example 10 was conducted except that the mixture wasstirred for 2 hours after addition of methylphenyldichlorosilane. Thereaction product had a weight average molecular weight of 1,300 (averagedegree of polymerization about 11).

EXAMPLE 14

The procedure of Example 10 was conducted except that a mixture of 450ml of THF and 150 ml of toluene was used as a solvent. The reactionproduct had a weight average molecular weight of 17,900 (average degreeof polymerization about 149).

EXAMPLE 15

The procedure of Example 10 was repeated except that 73 g (0.33 mol) ofp-ethylphenylmethyldichlorosilane was used as the raw material. Thereaction product had a weight average molecular weight of 22,200(average degree of polymerization about 150).

EXAMPLE 16

The procedure of Example 10 was repeated except that 82 g (0.33 mol) ofp-butylphenylmethyldichlorosilane was used as the raw material. Thereaction product had a weight average molecular weight of 17,200(average degree of polymerization about 98).

EXAMPLE 17

The procedure of Example 10 was repeated except that 65 g (0.33 mol) ofcyclohexylmethyldichlorosilane was used as the raw material. Thereaction product had a weight average molecular weight of 13,900(average degree of polymerization about 111).

EXAMPLE 18

The procedure of Example 10 was repeated except that 32 g (0.16 mol) ofmethylphenyldichlorosilane and 21 g (0.16 mol) of dimethyldichlorosilanewere used as the raw materials. The reaction product had a weightaverage molecular weight of 14,700.

EXAMPLE 19

Into a 100 ml-vol. eggplant type flask equipped with a three waystop-cock were placed 50 g of granular magnesium, 13.3 g of anhydrouslithium chloride (LiCl) and 8.6 g of anhydrous zinc chloride (ZnCl₂).The mixture was dried with heating to 50° C. under a reduced pressure of1 mmHg. Dry argon gas was introduced into the reactor. Added were 220 mlof tetrahydrofuran (THF) predried over sodium-benzophenone ketyl,followed by about 30 minutes of stirring at room temperature. Sixty-fourgrams (0.33 mol) of methylphenyldichlorosilane purified by distillationwas added with a syringe. The mixture was stirred at room temperaturefor about 15 hours. The stirring was effected by placing into thereactor, magnet chips 7 mm in diameter and 30 mm in length and stirringthe mixture with a magnetic stirrer (number of revolutions 1,350 rpm).

After completion of stirring, the molecular weight of the reactionproduct was measured. It was found that the reaction product had aweight average molecular weight of 16,600 (average degree ofpolymerization about 138). A mass spectrometric analysis confirmed thatthe reaction product was chlorinated at both ends.

EXAMPLE 20

The procedure of Example 19 was repeated with the exception of using 8.5g of anhydrous copper chloride (CuCl₂) in place of anhydrous zincchloride (ZnCl₁₂) and stirring the mixture for 72 hours after additionof methylphenyldichlorosilane. The reaction product had a weight averagemolecular weight of 18,900 (average degree of polymerization about 158).

EXAMPLE 21

The procedure of Example 19 was conducted except that the mixture wasstirred for 5 hours after addition of methylphenyldichlorosilane. Thereaction product had a weight average molecular weight of 6,300 (averagedegree of polymerization about 53).

EXAMPLE 22

The procedure of Example 19 was repeated with the exception of revolvinga magnetic stirrer at 720 rpm. The reaction product had a weight averagemolecular weight of 8,300 (average degree of polymerization about 69).

EXAMPLE 23

The procedure of Example 19 was repeated except that 73 g (0.33 mol) ofp-ethylphenylmethyldichlorosilane was used as the raw material and thatthe mixture was stirred for 48 hours after addition of the raw material.The reaction product had a weight average molecular weight of 13,900(average degree of polymerization about 94).

EXAMPLE 24

The procedure of Example 19 was repeated except that a mixture of 33 g(0.17 mol) of n-hexylmethyl-dichlorosilane and 32 g (0.17 mol) ofmethylphenyldichlorosilane was used as the raw material. The reactionproduct had a weight average molecular weight of 2,070 (average degreeof polymerization about 170).

EXAMPLE 25

The procedure of Example 19 was repeated except that a mixture of 6.5 g(0.033 mol) of cyclohexylmethyldichlorosilane and 57.5 g (0.30 mol) ofmethylphenyldichlorosilane was used as the raw material. The reactionproduct had a weight average molecular weight of 16,200 (average degreeof polymerization about 134).

EXAMPLE 26

The procedure of Example 19 was repeated except that a mixture of 6.5 g(0.033 mol) of 1,1,3,3-tetramethyl-1,3-dichlorodisiloxane and 57.5 g(0.30 mol) of methylphenyldichlorosilane was used as the raw material.The reaction product had a weight average molecular weight of 9,800(average degree of polymerization about 81).

Examples 27-46 given below illustrate the synthesis of polysilaneshaving phenol groups at both ends.

EXAMPLE 27

(Grignard Reaction)

A 2 liter-vol. reactor equipped with a dropping funnel, a reflux tubeand a stirrer was charged with 17.8 g (0.73 mol) of flakes of Mg afterwhich dry argon gas was introduced. Then, 300 ml of THF predried oversodium-benzophenone ketyl was added and 144 g (0.67 mol) ofp-methoxymethoxybromobenzene was added dropwise to produce a Grignardreagent. Thereafter, the reaction product prepared in Example 1 (THFsolution of a polysilane chlorinated at both ends) was added, followedby stirring at room temperature for about 24 hours.

After completion of the reaction, 300 ml of water was gradually addedwith cooling to inactivate the excess Grignard reagent. The reactionmixture was extracted with ether. The ether layer was dried overanhydrous MgSO₄ and concentrated, giving 60 g of an unpurifiedpolysilane (polysilane having methoxymethyl-protected phenol groupsintroduced at both ends).

(Purification)

The unpurified polysilane was re-dissolved in 20 ml of THF. Withstirring, a mixture of 600 ml of methanol and 150 ml of water was addeddropwise. The impurities were removed by re-precipitation, whereby animpurity-free polysilane was produced in the form of a white solid. Thesupernatant was removed by decantation after which the residue wasdried, giving 45 g of a polysilane. The polysilane was structurallyanalyzed by ¹H-NMR and was found to be a polysilane having phenol groupsat both ends, the phenol groups containing hydroxyl groups protectedwith methoxymethyl.

(Deprotection Reaction)

Added to 45 g of obtained polysilane were 175 ml of THF, 50 ml of waterand 20 ml of concentrated hydrochloric acid. The mixture was stirred at40° C. for about 24 hours. After completion of the reaction, thereaction mixture was extracted with 200 ml of ether. The ether layer waswashed with 50 ml of water twice. Thereafter the ether layer was driedover anhydrous MgSO₄ and concentrated, giving 40 g of an unpurifiedpolysilane (polysilane having phenol groups at both ends).

(Purification)

The unpurified polysilane was re-dissolved in 150 ml of a good solventTHF. With stirring, 3 liter of a poor solvent ethanol was addeddropwise. The impurities were removed by re-precipitation, whereby apolysilane was produced in the form of a white solid. The supernatantwas removed by decantation after which the residue was dried, giving 18g of a polysilane. The polysilane was structurally analyzed by ¹H-NMR,IR and UV (see FIGS. 1, 2 and 3) and was confirmed to have phenol groupsintroduced at both ends. The ¹H-NMR determination was carried out usingJNM-GX 270 manufactured by JEOL and deuterated chloroform as a solvent.The IR determination was carried out by a KBr method using FTIR-7000manufactured by JASCO. The UV determination was carried out using U-3410manufactured by HITACHI, LTD. and THF as a solvent (the same analyseswere effected in subsequent Examples).

The molecular weight of the reaction product was measured. The producthad a weight average molecular weight of 19,200 (average degree ofpolymerization about 158).

EXAMPLE 28

A reaction was conducted in the same manner as in Example 27 with theexception of using the reaction product prepared in Example 3 as thepolysilane chlorinated at both ends. In the purification aftercompletion of the deprotection reaction, methanol was used in place ofethanol as the poor solvent. The procedure gave a polysilane of 6,100 inweight average molecular weight (average degree of polymerization about49) which had phenol groups introduced at both ends. FIGS. 4, 5 and 6show ¹H-NMR, IR and UV charts, respectively.

EXAMPLE 29

A reaction was conducted in the same manner as in Example 27 with theexception of using the reaction product prepared in Example 4 as thepolysilane chlorinated at both ends. In the purification aftercompletion of the deprotection reaction, 25 ml of THF was used as a goodsolvent and a mixture of 400 ml of methanol and 100 ml of water was usedas a poor solvent. The procedure gave a wax-like polysilane of 1,300 inweight average molecular weight (average degree of polymerization about9) which had phenol groups introduced at both ends.

EXAMPLE 30

A reaction was conducted in the same manner as in Example 27 with theexception of using the reaction product prepared in Example 5 as thepolysilane chlorinated at both ends. As a result, a polysilane havingphenol groups introduced at both ends was prepared.

EXAMPLE 31

A reaction was conducted in the same manner as in Example 27 with theexception of using the reaction product prepared in Example 6 as thepolysilane chlorinated at both ends. As a result, a polysilane havingphenol groups introduced at both ends was prepared.

EXAMPLE 32

A reaction was conducted in the same manner as in Example 27 with theexception of using the reaction product prepared in Example 7 as thepolysilane chlorinated at both ends. As a result, a polysilane havingphenol groups introduced at both ends was prepared.

EXAMPLE 33

A reaction was conducted in the same manner as in Example 27 with theexception of using the reaction product prepared in Example 8 as thepolysilane chlorinated at both ends. As a result, a polysilane havingphenol groups introduced at both ends was prepared.

EXAMPLE 34

A reaction was conducted in the same manner as in Example 27 with theexception of using the reaction product prepared in Example 9 as thepolysilane chlorinated at both ends. The procedure gave a polysilane of17,800 in weight average molecular weight (average degree ofpolymerization about 148) which had phenol groups introduced at bothends.

EXAMPLE 35

A reaction was conducted in the same manner as in Example 27 with theexception of using 163 g (0.67 mol) of a halogenated phenol derivativewherein the hydroxyl group of p-(β-bromoethyl)phenol was protected withmethoxymethyl group in place of 144 g (0.67 mol) ofp-methoxymethoxybromobenzene. The procedure gave a polysilane of 18,300in weight average molecular weight (average degree of polymerizationabout 150) which had the phenol derivatives introduced at both ends.

EXAMPLE 36

A reaction was conducted in the same manner as in Example 27 with theexception of using the reaction product prepared in Example 3 as thepolysilane chlorinated at both ends and using 163 g (0.67 mol) of ahalogenated phenol derivative wherein the hydroxyl group ofp-(β-bromoethyl)-phenol was protected with methoxymethyl group in placeof 144 g (0.67 mol) of p-methoxymethoxybromobenzene. The procedure gavea polysilane of 6,100 in weight average molecular weight (average degreeof polymerization about 49) which had the phenol derivatives introducedat both ends. FIGS. 7, 8 and 9 show ¹H-NMR, IR and UV charts,respectively.

EXAMPLE 37

A reaction was conducted in the same manner as in Example 28 with theexception of using the reaction product prepared in Example 12 as thepolysilane chlorinated at both ends. As a result, a polysilane havingphenol groups introduced at both ends was prepared.

EXAMPLE 38

A reaction was conducted in the same manner as in Example 29 with theexception of using the reaction product prepared in Example 13 as thepolysilane chlorinated at both ends. As a result, a polysilane havingphenol groups introduced at both ends was prepared.

EXAMPLE 39

A reaction was conducted in the same manner as in Example 27 with theexception of using the reaction product prepared in Example 15 as thepolysilane chlorinated at both ends. As a result, a polysilane havingphenol groups introduced at both ends was prepared.

EXAMPLE 40

A reaction was conducted in the same manner as in Example 27 with theexception of using the reaction product prepared in Example 19 as thepolysilane chlorinated at both ends. The procedure gave a polysilane of16,700 in weight average molecular weight (average degree ofpolymerization about 138) which had phenol groups introduced at bothends. FIGS. 10 and 11 show ¹H-NMR and UV charts, respectively.

EXAMPLE 41

A reaction was conducted in the same manner as in Example 27 with theexception of using the reaction product prepared in Example 20 as thepolysilane chlorinated at both ends. The procedure gave a polysilane of19,000 in weight average molecular weight (average degree ofpolymerization about 158) which had phenol groups introduced at bothends.

EXAMPLE 42

A reaction was conducted in the same manner as in Example 27 with theexception of using the reaction product prepared in Example 23 as thepolysilane chlorinated at both ends. The procedure gave a polysilane of14,000 in weight average molecular weight (average degree ofpolymerization about 94) which had phenol groups introduced at bothends. FIGS. 12 and 13 show ¹H-NMR and UV charts, respectively.

EXAMPLE 43

A reaction was conducted in the same manner as in Example 27 with theexception of using the reaction product prepared in Example 24 as thepolysilane chlorinated at both ends. The procedure gave a polysilanewith a weight average molecular weight of 20,800 (average degree ofpolymerization about 170) wherein phenol groups were introduced at bothends.

EXAMPLE 44

A reaction was conducted in the same manner as in Example 27 with theexception of using the reaction product prepared in Example 25 as thepolysilane chlorinated at both ends. The procedure gave a polysilanewith a weight average molecular weight of 16,300 (average degree ofpolymerization about 134) which had phenol groups introduced at bothends. FIGS. 14 and 15 show ¹H-NMR and UV charts, respectively.

EXAMPLE 45

A reaction was conducted in the same manner as in Example 27 with theexception of using the reaction product prepared in Example 26 as thepolysilane chlorinated at both ends. The procedure gave a polysilanewith a weight average molecular weight of 9,900 (average degree ofpolymerization about 81) which had phenol groups introduced at bothends.

EXAMPLE 46

A reactor equipped with a dropping funnel, a reflux tube and a stirrerwas charged with 15 g (0.65 mol) of sodium and 300 ml of dry toluene.After dry argon gas was introduced, 64 g (0.33 mol) ofmethylphenyldichlorosilane was added dropwise under reflux conditions(110° C.). After dropwise addition, reflux was continued for about 3hours. After completion of the reaction, the supernatant wasconcentrated, whereby a polysilane was produced (Kipping method). Theobtained polysilane had a weight average molecular weight of 47,500(average degree of polymerization about 396).

The Grignard reaction and a deprotection reaction were conducted in thesame manner as in Example 27 using the obtained polysilane. Phenolgroups were introduced at both ends at a ratio of 35%.

What is claimed is:
 1. A polysilane represented by the formula (1)

wherein R is hydrogen atom, alkyl group, aryl group, alkoxy group, aminogroup or silyl group; R's may be the same or at least two of them may bedifferent from each other; each hydroxyl group is in the p-position orm-position; and n is 13 to 8,500.
 2. A process for preparing apolysilane having phenol groups at both ends which is represented by theformula (1)

wherein R is hydrogen atom, alkyl group, aryl group, alkoxy group, aminogroup or silyl group; R's may be the same or at least two of them may bedifferent from each other; each hydroxyl group is in the p-position orm-position; and n is 13 to 8,500, the process comprising the steps of(a) conducting the Grignard reaction between (i) a polysilane havinghalogen atoms at both ends which is represented by the formula (2)

wherein R and n are as defined above; and X is halogen atom, and (ii) aGrignard reagent prepared by reacting magnesium with ahydroxyl-protected halogenated phenol represented by the formula (3)

wherein R is hydroxyl-protecting group, and represents alkyl group,alkoxyalkyl group, silyl group, acyl group, alkylthioalkyl group oralkylsulfoxy group; protected hydroxyl group is in the p-position orm-position; and X₁ is halogen atom, thereby producing a polysilanerepresented by the formula (4)

wherein R, R₁, the position of protected hydroxyl group and n are asdefined above although variant depending on the starting materials; and(b) reacting the polysilane of the formula (4) with an acid.
 3. Theprocess according to claim 2 which is characterized in that thepolysilane having halogen atoms at both ends which is represented by theformula (2)

wherein R is hydrogen atom, alkyl group, aryl group, alkoxy group, aminogroup or silyl group; R's may be the same or at least two of them may bedifferent from each other; n is 13 to 8,500; and X is halogen atom, isproduced by subjecting to an electrode reaction a dihalosilanerepresented by the formula (5)

wherein m is 1 to 3; R is hydrogen atom, alkyl group, aryl group, alkoxygroup, amino group or silyl group; 2 R's in the case of m=1, 4 R's inthe case of m=2, or 6 R's in the case of m=3 may be the same or at leasttwo of them may be different from each other; and X is halogen atom,using Mg or a Mg-based alloy as the anode, a lithium salt as asupporting electrolyte and an aprotic solvent as a solvent with orwithout use of a halogenated metal as a current carrying aid.
 4. Theprocess according to claim 2 which is characterized in that thepolysilane having halogen atoms at both ends which is represented by theformula (2)

wherein R is hydrogen atom, alkyl group, aryl group, alkoxy group, aminogroup or silyl group; R's may be the same or at least two of them may bedifferent from each other; n is 13 to 8,500; and X is halogen atom, isproduced by reducing a dihalosilane represented by the formula (5)

wherein m is 1 to 3; R is hydrogen atom, alkyl group, aryl group, alkoxygroup, amino group or silyl group; 2 R's in the case of m=1, 4 R's inthe case of m=2, or 6 R's in the case of m=3 may be the same or at leasttwo of them may be different from each other; and X is halogen atom,using Mg or Mg-based alloy in an aprotic solvent in the presence of alithium salt and a halogenated metal.
 5. A polysilane represented by theformula (6)

wherein R is hydrogen atom, alkyl group., aryl group, alkoxy group,amino group or silyl group; R's may be the same or at least two of themmay be different from each other; Y is CH₂, C₂H₄, C₃H₆, C₄H₈, O or S;each hydroxyl group is in the p-position or m-position; and n is 13 to8,500.
 6. A process for preparing a polysilane having phenol groups atboth ends which is represented by the formula (6)

wherein R is hydrogen atom, alkyl group, aryl group, alkoxy group, aminogroup or silyl group; R's may be the same or at least two of them may bedifferent from each other; Y is CH₂, C₂H₄, C₃H₆, C₄H₈, O or S; eachhydroxyl group is in the p-position or m-position; and n is 13 to 8,500,the process comprising the steps of (a) conducting the Grignard reactionbetween (i) a polysilane having halogen atoms at both ends which isrepresented by the formula (2)

wherein R and n are as defined above; and X is halogen atom, and (ii) aGrignard reagent prepared by reacting magnesium with ahydroxyl-protected halogenated phenol derivative represented by theformula (7)

wherein R₁ is hydroxyl-protecting group, and represents alkyl group,alkoxyalkyl group, silyl group, acyl group, alkylthioalkyl group oralkylsulfoxy group; Y is CH₂, C₂H₄, C₃H₆, C₄H₈, O or S; protectedhydroxyl group is in the p-position or m-position; and X₁ is halogenatom, thereby producing a polysilane represented by the formula (8)

wherein R, R₁, Y, the position of protected hydroxyl group and n are asdefined above although variant depending on the starting materials; and(b) reacting the obtained polysilane with an acid. 7.The processaccording to claim 6 which is characterized in that the polysilanehaving halogen atoms at both ends which is represented by the formula(2)

wherein R is hydrogen atom, alkyl group, aryl group, alkoxy group, aminogroup or silyl group; R's may be the same or at least two of them may bedifferent from each other; n is 13 to 8,500; and X is halogen atom, isproduced by subjecting to an electrode reaction a dihalosilanerepresented by the formula (5)

wherein m is 1 to 3; R is hydrogen atom, alkyl group, aryl group, alkoxygroup, amino group or silyl group; 2 R's in the case of m=1, 4 R's inthe case of m=2, or 6 R's in the case of m=3 may be the same or at leasttwo of them may be different from each other; and X is halogen atom,using Mg or a Mg-based alloy as the anode, a lithium salt as asupporting electrolyte and an aprotic solvent as a solvent with orwithout use of a halogenated metal as a current carrying aid.
 8. Theprocess according to claim 6 which is characterized in that thepolysilane having halogen atoms at both ends which is represented by theformula (2)

wherein R is hydrogen atom, alkyl group, aryl group, alkoxy group, aminogroup or silyl group; R's may be the same or at least two of them may bedifferent from each other; n is 14 to 8,500; and X is halogen atom, isproduced by reducing a dihalosilane represented by the formula (5)

wherein m is 1 to 3; R is hydrogen atom, alkyl group, aryl group, alkoxygroup, amino group or silyl group; 2 R's in the case of m=1, 4 R's inthe case of m=2, or 6 R's in the case of m=3 may be the same or at leasttwo of them may be different from each other; and X is halogen atom,using Mg or Mg-based alloy in an aprotic solvent in the presence of alithium salt and a halogenated metal.